Chains are typically used in both bicycles and motorcycles as a means of transferring the rotary motion of the riders pedaling action or the motorcycle's motor to the rear wheel. The chain is especially useful at transferring this rotary motion to a variety of gears by use of a gear shifter. The nature of the chain, having a number of links that can pivot with respect to each other, allows the chain to thread between gears in a very flexible manner.
Motorcycle and bicycle chains are generally configured with a number of link pairs, which are connected to each other by side plates. The link pair has two link pair members. A first link pair member of a first link pair is connected to a first end of a side plate. The second end of the side plate is then also connected to a first link pair member of a second link pair. These connections are made by chain pins, which are press-fit into the link pair members and side plate.
The chains may be supplied in certain standardized lengths, which may be too long or two short for the exact cycle to which it is to be fitted. In addition, links of chains may become damaged by being bent, chipped, or otherwise deformed. It may be necessary to replace these links in order that the chain is not to fail or present a safety hazard. In either case, the chain may be “broken” by removing the chain pin that joins the links. When the link is broken at both ends, the link can be removed entirely and the neighboring links reattached, or a replacement link may replace the damaged one, and the chain pins then replaced to reconnect the chain.
The chain can similarly be shortened by removing links or lengthened by adding links and then replacing the connecting chain pins. It is sometimes the practice to include one special link called a “master link” on which breaking or rejoining is commonly performed. This master link is sometimes different in shape or color than the rest of the links and may employ rivets to permanently lock the chain pins of the master link in place.
Before the 1970's, most all chains came with a clip type master link. This master link could be removed simply with a pair of pliers by removing the safety clip. The only time it became necessary to break a chain was to shorten a length of chain to be installed. Rivet style master links were developed in the early 1970's because the more powerful motorcycles were having issues with breaking chains during hard acceleration. Shortly after, in the late 1970's O ring chains were introduced with press on rivet master links to increase durability by sealing the chain from water and debris. Thus the chain riveter was developed for use with these types of chains.
Most of the current chains use either rivet “hollow nose master links” or “quad stake master links”. In the motorcycle world, hollow nose master links are much more common than the quad stake but it is generally accepted that the quad stake is a more secure method.
FIG. 1 shows a drawing of a chain 1, with its various parts and elements. A chain 1 includes link pairs 2, which have a pair of link pair members 3. The links 2 are joined by side plates 4 and possibly by master links 10, which can be thought of as a specialized type of side plate 4, which have a first end 7 and a second end 8. The link pairs 2 shown include a first link pair member 5, which for this discussion will be the link pair member on the right, and a second link pair member 6, which for this discussion will be the link pair member on the left. Thus the first link pair member 5 of a first link pair 2 is connected to the first end 7 of side plate 4, and the second end 8 of side plate 4 connects to the second link pair member 6 of a second link pair 2. Connections between the link pair members and the side plates are made by chain pins 9, which extend through the side plates 4 through the link pair members 2 and finally through a lower side plate 4.
A master link 10 is produced by taking a side link 4 which has two chain pins 9 which are press-fit into holes in the side plate 4. A master link 10 is shown in FIG. 2, including chain pins configured as rivets 11. The top side plate 4 has been pressed onto the rivets 11, and then the tips 12 of the rivets 11 have been spread to prevent removal. It may be possible to later press the rivets out of the master link 10 and thus break the chain 1, although rivets 11 are generally used to make a more permanent connection. These rivets may be of the hollow nose master link or quad stake master link types and a different type of rivet head tip is generally used for the two different types. A hollow nose rivet 13 is shown in FIG. 2.
There are several reasons why a user may want to break a chain and then rivet it. These include:
Gearing change. When installing a larger or smaller sprocket to change the final drive it is often necessary to add or remove a link or two so that the wheel can be kept within the allowable wheel adjustment.
Replacement. New style O ring or press on link chains may not come apart unless the chain is physically cut. A chain breaker is required to remove the old master link and install the new one.
Engine removal. It is not possible on most motorcycles to remove the front sprocket because of the close clearance between the frame and sprocket without first breaking and removing the chain. After the chain is removed it is possible to remove and replace the front sprocket known as the “counter shaft sprocket”.
Chain repair tools have existed for years. One such repair tool is manufactured by Motion Pro, Inc. An example of this repair tool with instructional pages on its use is found at:
http://www.motionpro.com/tech/articles/chain_breaker_and_riveting tool/
Images from this instructional page are included in this discussion, which detail the use of the prior repair tool, and which are included in FIGS. 3-8. The included instructions aid in the general understanding of the use of this type of tool.
Referring now to FIGS. 3-4, a chain repair tool 20 is shown in a cut-away view in the process of breaking a chain 1. The repair tool 20 includes a body 22, an body bolt 24, having a head 26, a drive bolt 28, having a drive bolt handle 30, a breaking pin 32 and a main handle 34. A spring 36 is provided which fits between the breaking pin 32 and the interior of the body bolt 24. A hole 40 is also provided to allow the chain pin 9 to pass out of the repair tool 20
The repair tool 20 is assembled by threading the body bolt 24 into the body 22. The breaking pin 32 is inserted into the spring 36 and both are dropped into the body bolt 24 with the spring 36 under the tip head 38. The drive bolt 28 is threaded into the body bolt 24 above the breaking pin 32.
The chain repair tool 20 is placed over the chain 1 as shown in FIG. 4. The breaking pin 32 must be withdrawn at least 2 mm into the body bolt 24 to clear the end of the chain pin 9. One end of the chain pin 9 will be held in position by the end of the body bolt 24, while the other end is held in position by the hole 40 of the tool body 22.
The body bolt 24 is tightened securely against the side plate 4 of the chain 1. The drive bolt 28 is tightened by the drive bolt handle 30 or a 14 mm wrench until the chain pin 9 is pushed completely out and through the hole 40 in the tool body 22. The chain 1 has then been broken.
If side plates 4 are to be replaced, and pressed into place, the repair tool 20 must be reconfigured for pressing. The repair tool 20 is re-assembled as shown in FIG. 5 for pressing the side plates 4. The body bolt 24 will be threaded into the body 22, with the breaking pin 32, spring 36 and drive bolt 28 removed. Two press plates 42 are provided. One press plate 44 with the holes will be inserted into the body bolt 24, and another press plate 46 with a groove will be placed in the hole 40 in the tool body 22.
The new chain 1 with the master link 10, side plate 4 and o-rings (if applicable) is assembled. The assembled master link 10 is positioned in the repair tool 20 as shown in FIG. 6. The side plate 4 with the chain pins 9 will be placed against the grooved press plate 46, and the side plate with the holes 4 will be placed against the press plate with the holes 44.
The body bolt 24 is lightly hand-tightened using a 14 mm wrench 15 until the press plates 44, 46 touch the master link side plates 4. The master link chain pins are checked for proper alignment with the groove and holes in the press plates 44, 46 before final tightening. The body bolt 24 is then tightened until the chain pins 9 (not visible) protrude past the face of the side plate 4.
If a link is to be riveted in place, the repair tool 20 is again reconfigured, as shown in FIGS. 7-8, which show the repair tool 20 configured for riveting hollow-nosed master link pins. The body bolt 24 is threaded into the body 22. The rivet tip 48 (not visible in this figure) is inserted into the body bolt 24. The drive bolt 28 is threaded into the body bolt 24. An anvil 50 is placed in the hole 40 in the tool body 22.
The new side plates 4 of the master link 10 should already be pressed as described above so that the chain pin 9 (not visible) protrudes past the face of the side plate 4 of the master link 10. The repair tool 20 is positioned over the rivet 11 to be riveted, with the hollow end 52 (not visible) of the chain pin 9 facing the rivet tip 48, and the solid end 54 facing the anvil 50.
The body bolt 24 is tightened securely against the side plate 4 of the chain 1. Then using a 14 mm wrench, the drive bolt 28 is tightened very tightly until the rivet tip 48 spreads the hollow nose 52 of the rivet 11. The hollow end 52 of the rivet 11 should be flared over the side plate 4 just enough so that the side plate 4 is solidly held in place. This procedure is repeated on the other rivet 11. FIG. 2 shows a master link 10 with properly flared hollow-nosed rivets 13.
As is apparent from the previous discussion, the prior repair tool 20 requires a number of parts, some of which are not used at any one time, and therefore may be easily misplaced or lost unless they are kept together in a carrying case or tool kit. Additionally, it may be unclear at any one time whether the tool is configured for “breaking”, “pressing” or “riveting”, and separate attachments may be required for each of these operations. Re-configuring the tool 20 for the various operations may be confusing for users who have limited familiarity with the chain repair.
Therefore, there is a need for a chain repairing tool for attaching, detaching and riveting chain links that combines features of several individual tools into a single convenient unit, which uses fewer parts, which is more easily converted from one configuration to another, and which is clear for which of the various operations of breaking, pressing and riveting the tool is configured